(OT) Rebuilding laptop batteries

I'm asking this question on here because I've read several times about some of you rebuilding the battery packs for cordless tools.
Have any of you rebuilt the battery packs for laptop computers? Can this be done? They want more than I paid for the computer for a replacement, so it's either rebuild it, or replace the computer and just use the old computer where there is an outlet.
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On Sun, 28 Oct 2012 16:48:30 -0600, snipped-for-privacy@none.com wrote:

There are a LOT of third party battery suppliers that will sell you a brand new battery for less than you can rebuild the original for. I've purchased quite a few brand new batteries for under $50.
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On Sun, 28 Oct 2012 18:16:56 -0400, snipped-for-privacy@snyder.on.ca wrote:

I replaced my ThinkPad battery with an off-brand. I think it was $30. Lenovo wanted more than $120. Works fine.
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On 10/28/2012 3:48 PM, snipped-for-privacy@none.com wrote:

It's a crap shoot. Depends a lot on the technology and the vendor. I've had zero luck with IBM. Once the "chip" shuts off, it's all over. Dells resort to an error condition, but the pack works. Had one with a PIC processor...resetting the processor fixed it. Others have no issues at all. Got one that will charge, but the computer won't run on AC, it defaults to battery. Only way to charge it is to leave it off. Only way to run it on AC is to remove the battery.
You can buy software that claims to reset chips, but it costs more than a new pack. And it requires some hardware. Not clear if it's updated to the latest stuff. I've never found resetting info on the web.
Where are you gonna get QUALITY new cells for less than the price of the pack?
How are you gonna attach them? The fit is so tight in the plastic that even tabbed cells are a problem. Where are you gonna put the solder joint on the tab that still lets the case close. I bought a tab welder that greatly simplifies the situation.
What are you gonna do about mismatched cells?
What are you gonna do when you pick the wrong cells and it catches fire while your kid's surfing the web? I've rebuilt several packs, but there's no way I'd sell one in a used laptop. Liability risk is too high.
There are lots of how-to's on the web. Many resort to soldering directly to the cells. That's a disaster waiting to happen.
I understand your pain, but unless you're rebuilding many packs and are willing to invest in the equipment and training, my advice is to give it up.
You can buy external batteries that plug in the ac adapter socket. Not optimal, but they can work with different laptops.
Are we having fun yet?
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What brand and model is the laptop? What is the battery part number? What price have you been quoted?
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What do you mean when you say "when the chip shuts off"? Does the computer shut down when the battery gets too bad?
This is an IBM T-43 laptop.

Mine runs from the AC power cord just fine. I never tried it with the battery removed.

Please explain. Where is this chip and why does it fail?

<snip>
I've seriously considered using an external battery such as a motorcycle or garden tractor battery. They are small and light enough to carry easily. 90% of the time I run this computer on AC or plug it into my car's cigarette lighter. The internal battery only gives me about a half hour these days, (even if I leave it plugged in all the time when not in use), so it's becoming fairly useless. The meter says the battery is only operating at 47% capacity. Considering that, a brand new battery is only good for about an hour. I think an external battery should last much longer, and can be charged with a common battery charger too.

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On 10/29/2012 2:26 PM, snipped-for-privacy@none.com wrote:

OK, the "chip" is a small computer that keeps track of the battery and communicates with the laptop. Depending on the battery technology and the particular chip, there can be a lot going on.
The particular task important here is battery voltage monitoring. The chip tells the laptop what it thinks the remaining capacity is. The laptop is responsible for making sure that the battery is not overcharged or undercharged. But the battery chip also knows what are safe voltage levels and can disconnect the battery independent of the laptop's wishes.
When overdischarged, lithium cells are not only dead, they're unsafe. They can catch fire if you try to recharge them. Vendors don't like lawsuits, so they're very conservative about how low the cells can discharge. At some point, the chip PERMANENTLY disconnects the cells and there's nothing you can do externally to turn them back on. If you replace the cells, the voltage goes to zero and the chip latches off. New cells won't help, the chip is still turned off. They won't tell you how to turn it on from the internal bus. You'll find youtube videos on how people added power supplies to keep the chip powered while replacing the cells "hot". Another problem is that even if the chip doesn't turn the system off, it sometimes remembers the old battery capacity and reports that to the laptop which turns off based on the wrong number. It's always something.
I haven't tried replacing cells on anything newer than about 2006 vintage laptops. The safeguards seem to be more stringent with time.
My experience is that the primary failure mode for a laptop battery is increased internal resistance. I built a computer-controlled battery test system and verified that, at low current, a "bad" laptop battery can deliver almost all of it's rated electrons. But the laptop is a High current pulsed load.
The sense voltage is depressed by the internal series resistance and the voltage sense shuts the system down while there's still lots of electrons left to be had. That's compounded by the resistance raising the sense voltage under charge, so the charger shuts off before delivering the full number of electrons.
This could be fixed, but there are factors that prevent that.
1)customers want the smallest/lightest laptop possible. Bigger battery is not an option. Vendors advertise battery life under optimum conditions on day one. After that, you're on your own.
2)there's more profit in a replacement battery than there was in the whole laptop. That's why you don't find a standard battery that works in any laptop. That would make it a commodity and kill the profit margin.
Do not underestimate the safety issues in rebuilding battery packs. Back in the day of NiCd packs, I blew up one. If I hadn't been wearing safety glasses, I'd be typing this on a braille keyboard.
There's no way you'll save money rebuilding one or three packs. If you have time on your hands and a lot of equipment, it can be a fun hobby, until you get bored.
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If the computer remembers the battery capacity, what happens if a person gets a new battery? If the old battery was at (example 25%), then a brand new battery will only work at 25%.
I never knew it was so complicated to change a battery in these laptops. I think my plan to rig up an external motorcycle battery pack is looking better by the minute. I did remove the battery yesterday and was able to run the computer via power cord connected to AC outlet. If that battery is gonna shut down the computer so I cant use it at all, I wont be putting it back. From now on it will operate off AC or an external battery only.
Thanks for the extensive info about this.
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On 10/30/2012 11:16 AM, snipped-for-privacy@none.com wrote:

no,no,no...the battery pack can shut itself down, but it won't hurt your laptop. The situation that causes the pack to shut itself down is when you discharge it and set it on the self for years. Happens a lot with used laptops that sat in the basement for years before they showed up at the estate sale.
The primary reason I mentioned it is that when you disconnect the cells to replace them, the chip triggers the shutdown mechanism and you may not be able to recover a working pack even tho it has new cells.
I wont

That's not what I said. I said the "chip" (inside the battery pack) may remember the old capacity. The chips I've looked at track the battery capacity as it goes down. But they have no ability to track it if it goes up. Cuz, it never happens in a battery pack that hasn't been tampered.
Changing a battery is trivial. Changing the cells inside a battery is not. There's a lot of secrecy around the process so they can keep charging you big bux for new battery packs...and keep you from setting yourself on fire.
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On Tue, 30 Oct 2012 12:16:03 -0600, snipped-for-privacy@none.com wrote:

The batteries have a serial number. The laptop can keep track of several batteries.

I replaced mine with no problems. The laptop died recently (other problems) but the off-brand battery bought me couple of years.

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On Mon, 29 Oct 2012 15:26:26 -0600, snipped-for-privacy@none.com wrote:

All Lithium Ion battery packs have battery management systems built in to protect the cells. If the battery goes "dead" the battery management system shuts down and the battery cannot be recharged without resetting the battery manager - some can be easily reset - some are difficult, and some are impossible. No problem on NIMH batteries.
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On 10/28/2012 5:48 PM, snipped-for-privacy@none.com wrote:

I've had battery packs rebuilt at Batteries Plus with good results. The store can be somewhat more expensive than other places but the store tech has the proper equipment to spot weld the tabs onto the individual cells. The company also sells factory made laptop batteries at a fairly competitive retail price. You may have a store in your area. I like to spend money locally because I can get my hands around the throat of the merchant if there's ever a problem with the product. ^_^
http://www.batteriesplus.com /
TDD
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Ayuh. The Smrf approach to purchasing? "Excellent service, or I'll choke you blue."
Christopher A. Young Learn more about Jesus www.lds.org .
I've had battery packs rebuilt at Batteries Plus with good results. The store can be somewhat more expensive than other places but the store tech has the proper equipment to spot weld the tabs onto the individual cells. The company also sells factory made laptop batteries at a fairly competitive retail price. You may have a store in your area. I like to spend money locally because I can get my hands around the throat of the merchant if there's ever a problem with the product. ^_^
http://www.batteriesplus.com /
TDD
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wrote:

I can vouch for Batteries Plus. There are two within a five mile radius from me. I've never had a laptop battery rebuilt but have had tool batteries rebuilt with great success and long lasting. As DD stated, they have competitive pricing and if they don't have it, they can get it, though rare if they don't have it.
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snipped-for-privacy@none.com wrote:

Tried to.

Yes.
The problem is - because of insurance liability reasons, nobody -> and I mean NOBODY, will sell individual NiMH or Li-ion cells (the cells that you find in battery packs) to consumers / end-users.
The risk is that the batteries can do nasty things (like explode or get really hot and ignite) if they aren't recharged properly, and the only way that "the powers that be" are satisfied about these batteries getting into the hands of consumers is when they're sold as complete units, with integrated charging / monitoring electronics built-in.

If you want to chance it, buy the cheapest battery-pack you can find that has the same size of cells that you need - and when you get it, take it apart and get the cells out of it and rebuild your battery pack with them.
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theres talk of making it illegal to sell car repair parts to anyone but a certified mechanic, since say brakes improperly installed could create a ublic safety issue
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On Sun, 28 Oct 2012 16:48:30 -0600, snipped-for-privacy@none.com wrote in
batteries:

Have you tried Amazon.com? I got a new replacement battery from them for a 6 year old Dell laptop for $17.00. It works as well as the original. However if you have an Apple laptop, just throw it away.
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CRNG wrote:

I got one for my Toshiba laptop from e-bay. 18 dollars free shipping. Some instructions were with it, conditioning of the new battery information. First time I've seen that. The battery seems OK considering the cost.
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